Numerous applications exist in which it is desired to form repeating patterns having a small pitch (for example, a pitch of less than about 50 nanometers). For instance, integrated circuit fabrication may involve formation of a repeating pattern of memory-storage units (e.g., NAND unit cells, dynamic random access memory [DRAM] unit cells, cross-point memory unit cells, etc.).
A variety of methods have been developed for creating patterned masks suitable for patterning underlying materials during fabrication of integrated circuit components. A continuing goal of integrated circuit fabrication is to increase integrated circuit density, and accordingly to decrease the size of individual integrated circuit components. There is thus a continuing goal to form patterned masks having increasing densities of various patterned features.
A method showing some promise for creating repeating patterns to high density involves utilization of block copolymer to form the repeating patterns. Unfortunately, it is difficult to use block copolymer as patterned masks due to various difficulties presented in attempting to selectively remove some portions of block copolymer relative to others to create the patterned masks, and difficulties presented in attempting to transfer patterns from block copolymer masks into underlying materials. It would be desirable to develop new methods of utilizing block copolymer which address and/or circumvent such difficulties.